I had a slumber party birthday party taken away for bad behavior. I think I was about 2nd grade. I don't remember what I did but I do remember being warned and I remember that mom followed thru. Honestly it was awful, one mom didnt get the message and my little friend had to be turned away at the door gift in hand! Just because it was not fun though does not mean my mom made a parenting mistake. Punishments are not meant to be comfortable and you can bet I kept that in mind when I was being naughty. I think you should still aknowledge, her birthday, make her favorite dinner or whatever but I wouldnt back down on the no party.
I also agree with ignoring her during a tantrum. By trying to do everything you can to make her stop you are just feeding into it and giving her the power to control the situation.

__________________~Jessica~Adoring wife to Chris best mommy I can be to Jackson and Weston. I CD, ERF, EBF, BW, and kept my second boy intact!